This invention relates to a damper disk applicable to friction clutch discs of land vehicles.
In a type of known damper discs, a sub-plate is arranged between a radial flange of a hub splined to an output shaft and each of side plates which are a clutch plate and a retaining plate. A first friction member having small frictional force is arranged between the hub-flange and each sub-plate, and a second friction member having large frictional force is arranged between each side plate and each sub-plate. In this construction, when small torque is transmitted, and therefore relative torsion angle between the hub-flange and the side plates is small, slide occurs on the surface of each first friction member, so that small hysteresis torque occurs. When the transmitted torque increases to large value, and thereby the torsion angle increases to large value, slide occurs on the surface of each second friction member, so that large hysteresis torque occurs. In the disc in which the hysteresis torque changes as stated above, noises can be prevented during both idling and high power driving.
However in this known type of the damper disc, since the hub flange has large recesses through which stud pins connecting the sub-plates together and stop pins supported by the side plates pass, the strength of the hub flange is reduced by said large recesses. Therefore it is impossible to form large and long openings in the flange in which long torsion springs for efficiently absorbing torque vibration can be fitted, which results in disadvantage that desired effect for absorbing the torque vibration can not be obtained.
Accordingly, it is an object of the invention to provide a damper disc, wherein positions, shapes and sizes of notches and recesses for stop pins, stud pins are improved.
Other and further objects, features and advantages of the invention will appear more fully from the following description of the preferred embodiment of the invention.